This section provides background information related to the present disclosure which is not necessarily prior art. Vehicles can include one or more batteries that supply power to electrical devices (i.e., load) within the vehicle at various operating conditions of the vehicle. For example, as the main power source, a primary battery device can be used to start an engine of the vehicle and supply power to the electrical devices from an alternator connected to the engine. When the engine is off, the electrical devices may continue to receive power from the primary battery device until the electric charge of the primary battery device decreases to a preset threshold. The vehicle may also include an auxiliary battery device that may operate as a back-up battery for providing power to the electrical devices.
The primary battery device and the auxiliary battery device may be connected and disconnected from the load by way of mechanical switches, such as relays. While relays are capable of switching between the primary battery device and the auxiliary battery device, the relays present multiple disadvantages and challenges. For example, over time, contacts of the relays may begin to corrode or weld, and thus need to be cleaned, which reduces current handling capability of the relay. In addition, due to their size, the relays are typically mounted on a separate circuit board and, thus, require additional space in the vehicle. Therefore, there is a need for a more efficient and smaller battery switching system for controlling the connection of the batteries to the load and to each other.